Wavefields in a cased hole surrounded by a formation with transverse isotropy caused by axial stresses

Abstract Understanding acoustic field characteristics in the cased hole accompanied by stress is important for acoustical logging. This study investigates behavior of multipole wavefields a with perfect combination casing, cement, and formation under borehole-axial stress. The can be equivalent to transversely isotropic medium when uniaxial acts on based nonlinear elasticity theory. effect axial investigated. Numerical results show that phase slowness Stoneley, flexural, screw waves decreases an increase compressive With stresses, arrival times full waveforms decrease, amplitudes increase. These are similar open hole. For holes soft formations, excitation curves flexural shift low frequencies as increases; dispersion corresponding also exhibit shift, while do not have this pattern. excited dipole source quadrupole more prominent changes frequency spectra, integral larger than those We found responses sources sensitive